The electronic structure of organic sulfonyl compounds of the form RSO(2)G (G = -CI, -OH, -CH3) is investigated to evaluate the effect of aryl R groups on photocleavage of the S-G bond. Sulfur K-edge X-ray absorption spectroscopy (XAS) provides a direct measure of the empty low-lying molecular orbitals in these complexes and, in combination with DFT calculations, a detailed description of the bonding in these compounds. The presence of an aryl group bound to the sulfonyl moiety has a significant impact on the spectroscopy and electronic structure of the site. The analysis suggests that the SCI sigma. orbital is significantly affected by mixing with the aryl pi* manifold. This mixing is dependent upon the nature of G and is most pronounced in the sulfonyl chlorides, where the energy of the SCI sigma. orbital is lowered by similar to 0.5 eV. The observed mixing is best described as excited-state hyperconjugation of the aryl pi system into the SCI sigma. orbital. The magnitude of the effect can be estimated directly from the S K-edge XAS spectra. These results are discussed in relation to the observed photochemistry of RSO2CI, which is significantly enhanced when R = aryl as compared to alkyl substituents.